在非平稳杂波背景中，背景杂波平均功率的轻微变化会使虚警概率急剧上升。如果利用参考单元采样形成背景杂波功率水平估计，然后自适应调整检测阈值可以控制虚警概率。对于这种自适应阈值检测器，我们利用不变检验概念证明了在一定的弱约束条件下的一类检测器具有ＣＦＡＲ（ＣｏｎｓｔａｎｔＦａｌｓｅ Ａｌａｒｍ Ｒａｔｅ）性质，揭示了这类ＣＦＡＲ检测器的机理，为此类ＣＦＡＲ检测器提供了通用的证明方法 In the non-stationary clutter background, the slight change of the average power of the background clutter will cause the false alarm probability to rise sharply. If the reference unit samples are used to form the background clutter power level estimation, the false alarm probability can be controlled by adaptively adjusting the detection threshold. For this kind of adaptive threshold detector, we use invariant test to prove that a class of detectors with CFAR (Constant Frequency Alarm Rate) property under some weak constraints prove the mechanism of such CFAR detectors. To this end, Class-based CFAR detectors provide a general proof of method